Energy-dissipative improvement in high-speed print hammer mechanisms

ABSTRACT

A cooperative plurality of energy-dissipating means is incorporated into a high-speed mechanism so as to be sequentially activated and be operative upon a working member for timely extraction of precise quantities of excess kinetic energy and for producing long life and bounce-free fast operation of the working member. Incorporation of the invention into a high-speed printer wherein energy absorption from components of the printer is accomplished via structurally improved members is also disclosed.

United States Patent Johnston et al.

[451 Jan. 25, 1972 [54] ENERGY-DISSIPATIVE IMPROVEMENT IN HIGH-SPEED PRINT HAMMER MECHANISMS [72] Inventors: Lynn M. Johnston, West Milton; Chester G. Jones, Kettering; Harold D. Neal, Dayton, all of Ohio; Samuel A. Redman, Garden City, NY.

[73] Assignee: The National Cash Register Company,

Dayton, Ohio [22] Filed: Oct. 6, 1969 21 Appl. No.: 863,826

[52] U.S.CI. ..l01/93C [51 Int. Cl. ..B4lj 9/24 [58] Field ofSearch 101/93 C, 109, 93 R, 93 MN;

[ 56] References Cited UNITED STATES PATENTS 3,144,821, 8/1964 Drejza ..101/93C 3,145,650 8/1964 Wright ..101/93 C 3,359,921 12/1967 Arnold et a1. 101/93 C 3,183,830 5/1965 Fisher et a1 .1 101/93 C 3,266,418 8/1966 Russo.... 101/93 C 3,279,362 10/1966 Helms 101/93 C 3,289,575 12/1966 Wasserman. .....101/93 C 3,351,006 11/1967 Belson ..l0l/93 C 3,460,469 8/1969 Brown et a1. 101/93 C 3,504,623 4/1970 Stallcr ..101/93 C Primary Examiner-William B. Penn Attorney-Louis A. Kline and John J. Callahan [5 7] ABSTRACT A cooperative plurality of energy-dissipating means is incorporated into a high-speed mechanism so as to be sequentially activated and be operative upon a working member for timely extraction of precise quantities of excess kinetic energy and for producing long life and bounce-free fast operation of the working member. Incorporation of the invention into a highspeed printer wherein energy absorption from components of the printer is accomplished via structurally improved members is also disclosed.

22 Claims, 4 Drawing Figures PATENIEU JANZS I972 sum 1 or 2 DISPLACEMENT INVENTORS LYNN M. JOHNSTON CHESTER JONES HAROLD D. NEAL 8 SAMUEL A. REDMAN WITNESS BY M s M WN THEIR ATTORNEYS PATENTED JANZS 1972 3,636,868

sum 2 or 2 INVENTORS LYNN M. JOHNSTON CHESTER JONES HAROLD D. NEAL SAMUEL A. REDMAN WITNESS WWW 8 THEIR ATTORNEYS ENERGY-DISSIPATIVE IMPROVEMENT IN HIGH-SPEED PRINT HAMMER MECHANISMS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention pertains to improvements in the structure and operation of a high-speed mechanism and especially to improvements in solenoid-actuated printer mechanisms employed as peripheral equipment in electronic data-processing systems.

The invention further relates to structures and methods employed to remove discrete quantities of kinetic energy from members of a printer mechanism at sequential parts of the operating cycle; through energy removal, bounce-free printing at a high rate of speed and with long component life is achieved.

2. Description of the Prior Art In the prior art, the concept of operating a freely suspended print hammer between forward and rear impact surfaces is common. In these prior art inventions, it is common to use these impact surfaces to limit travel of the hammer member without investing them with energy-dissipating ability and without considering them as a part of a unified approach to dissipating energy from the print hammer mechanism.

In the prior art, it has also been known to place unidirectionally conductive elements and dissipative elements across an inductive coil in order that the voltage developed within the coil upon decrease of current flow be limited in magnitude, this magnitude limitation being especially necessary when the inductive coil is controlled by a semiconductor device, such as a transistor, having limited voltage capability. The prior art in magnetic circuit excitation is replete with examples of this technique applied to inductive devices such as cathode-ray tube deflection yokes, transformers, and filtering network reactors as well as electromechanical solenoids and solenoids coupled to a printing mechanism. The prior art speaks of the elements placed across the inductive coil in terms of their ability to limit coil voltage or in terms of their effect upon the current decay and mechanical time constants in the coil but does not consider them as part of a unified approach to dissipating energy from a moving member in a highspeed mechanism, as does the present invention.

The prior art in high-speed printing mechanisms discloses the use of a stationary member located within the enclosure defined by the printing hammer and its cantilever mounting springs to engage one cantilever spring at the hammers most forward position of travel and the other cantilever spring at the hammer's most rearward position of travel and by such engagement to halt motion of the hammer member near the desired forward and rearward travel extremities. In the present invention, it has been found desirable to engage the cantilever springs for stopping in a manner which is more positive and more effective than that revealed in the prior art.

SUMMARY The present invention provides for comprehensive sequential removal of excess kinetic energy from members of a highspeed printing mechanism in order that rapid printing free of undesirable bounce effects may be achieved and long operating life-be realized in the highly stressed members of a printing mechanism.v

The invention concerns a combination of energy dissipative methods and structures which are activated in sequence as the hammer is operated through a cycle of printing. One dissipation means is operative via inductive and electrical coupling with the print hammer driving member and is capable of removing a major quantity of the energy to be dissipated. Effective utilization of this major capability provides a new method of hammer operation of a high-speed printer.

DESCRIPTION OF THE DRAWINGS FIG. I of the drawings is an essential elements representation of a printer mechanism employing an energy dissipation according to the present invention.

FIG. 2 of the drawings is a curve showing the relationship between time and displacement for a print hammer actuating member in a printer mechanism operating in accordance with the present invention.

FIG. 3 of the drawings is a partial assembly view of a printer mechanism having a plurality of printing hammers and made in accordance with the present invention.

FIG. 4 of the drawings shows an electrical circuit coupled to an actuating solenoid of a printer mechanism for excitation and energy-dissipative purposes.

DESCRIPTION OF THE PREFERRED EMBODIMENT The energy-dissipative system of the present invention is disclosed by way of embodiment in a high-speed printing mechanism; utility of the invention is not limited to the printer art, however. A person skilled in the art of high-speed mechanism design will appreciate that the invention may also be applied in other mechanisms, such as textile machinery; business machines, including high-speed punches and sorting machines; and any mechanism having a high-speed moving member whose kinetic energy must be decreased during part of an operating cycle.

In FIG. 1 of the drawings, there is shown a high-speed printing mechanism in which the present invention is embodied. The mechanism shown in FIG. I may be classified as a highperformance printing mechanism in relation to its prior art counterparts. The illustrated mechanism is capable of operating with printing energy levels near 200,000 ergs while operating at a printing velocity near 200 inches per second and at rates up to 3,000 lines per minute.

In addition to a high operating energy level, the FIG. I mechanism is improved over the prior art from the viewpoint of overall printing speed, since it is possible, in this mechanism, for the hammer to leave rest position, strike the media to be printed, and return to home position within 5% milliseconds. In operation of the mechanism, time greater than this 5% milliseconds is allowed in order that mechanism parts may settle out or reach quiescent equilibrium before initiation of the next excitation event. The present invention also pertains to improved techniques for accomplishing this settling out through kinetic energy dissipation from the mechanism members.

In addition to high performance capability measured in terms of speed and operating energy level, the mechanism of FIG. I also provides desirable performance from the viewpoint of operating life; a life measured in hundreds of millions of printing cycles is commonly experienced for a mechanism such as that shown. This life is possible largely through the incorporation of energy-dissipative improvements which are part of the present invention.

The mechanism of FIG. I is shown to have major elements identified as a movable printing hammer member 28, a hammer-actuating solenoid assembly 54, a hammer backstop assembly 24, and a hammer penetration stop assembly 55. In FIG. 3, the relationship of these parts to a type carrier 152 and a ribbon, paper, and carbon complex -151 is shown.

In describing a high-speed printing mechanism such as that shown in FIG. 1, it is helpful to consider the energy flow into and out of the print-inducing hammer member. Because the quantity of energy required to perform the printing sequence (bringing media and ink and typefont together under pressure) is relatively small in comparison with that which must be imparted to the mechanism to effect motion of the printing parts at a useful speed, the energy flow viewpoint leads into one of the major requirements for a successful printing mechanism, that of effective dissipation of the mechanisms excess energy, energy not dissipated during the printing operation. In the present invention, a unified and comprehensive approach to the energy dissipation needs of a printing mechanism or other high-speed intermittent-motion mechanism is disclosed.

Improved removal of excess energy from movable members of a printing mechanism, even though it occurs before and after the printing portions of the operating cycle, will permit enhancement of the operating speed and operating life of a printing mechanism equally as well as will speed. improvements in the energizing and printing portion of the cycle, since it is customary to allocate more cycle time to events following the instant of printing-that is, events between the instant of printing and the time of initiating the next energizing cyclethan is devoted to events within the energizing cycle leading up to the printing instant. No useful purpose from the printer performance viewpoint is served by this large allocation of time after print, since the printer's function is not again performed until the next printing impact.

It is clear that the large allocation of printer cycle time following the instant of print is imposed primarily by a need to remove kinetic energy from the printing mechanism and thereby return it to a state of quiet and to remove this energy in a fashion which is relatively gentle to the involved printer members so that long and useful operating life is possible.

Printing performance of the FIG. 1 printer embodiment is significantly improved by an array of energy-absorbing means which are activated in selected portions of the printer cycle and which serve to remove precise quantities of kinetic energy from the mechanism during desired portions of the operating cycle. This array of energy-absorbing means includes a cooperating arrangement of five separate energy-absorbing means each active in a successively later portion of the operat ing cycle. Although the specification speaks of incorporating all five energy-absorbing means into a printer, it is clear that many combinations including only a portion of the five are possible and may be used in other mechanism embodiments.

Disclosure of the five energy absorbing means is made in this specification by way of sequentially describing events which occur in the FIG. 1 mechanism, beginning with aperiod of rest having the parts in the state shown in FIG. I.

In FIG. I, the mechanism in which the invention is embodied is shown in the quiescent state. In this quiescent state, a spring 19 exerts a small force on the armature arm 17 to urge it into contact with the backstop assembly 24. The force of the small spring I9 is transmitted to the printing hammer member 28 by way of a second spring member 29, named the pigtail spring member. The force exerted by the small spring 19 and transmitted by the pigtail spring 29 is made sufficiently large to hold the hammer member 28 away from the paper to be printed (located across the top of the drawing, as shown by the numeral 151 in FIG. 3 of the drawings) and to hold the cantilever hammer support springs 31 in a neutral, or close to natural, position. The end of the armature arm 17 in FIG. I is covered by a boot member 22, which engages both the stop assembly 24 and an impactand wear-resistant surface 42 on the end of the hammer member 28. Between the hammer impact surface 42 and the armature arm boot 22 is an interface designated by the numeral 52; as shown in the quiescent position of FIG. I, the space at the interface 52 is small or nonexistent, since the hammer member 28 and the armature boot 22 are in physical contact with each other. In a later portion of the operating cycle, the space at 52 assumes larger dimensions.

In the operation of the mechanism shown in FIG. 1, the armature arm 17 is accelerated upward by the effect of an elec trical current flowing in the coils of the solenoid assembly 54. Acceleration of the armature arm 17 and the hammer assembly (which includes the hammer member 28 and the springs 31) continues until the airgap space between the armature member 20 and the stationary poles in the solenoid assembly 54 is reduced to zero. In the particular solenoid shown in FIG. 1, this airgap is located within the length of the solenoid coils so as to be invisible in the FIG. I view. Upon the solenoid airgaps being reduced to zero, the solenoid armature 20 and the armature arm 17 are decelerated to zero velocity and, in so doing, dissipate kinetic energy in the form of heat and sound produced by elastic stretching of the metal parts in the solenoid assembly.

' Motion of the hammer member 28 continues during deceleration of the solenoid armature 20 and the armature arm I7, with the hammer during this time behaving essentially as a ballistic body moving in free flight under the influence of kinetic energy which it received during acceleration. During this ballistic flight, with the solenoid armature arm 17 held motionless, the hammer member 28 is stretching, or transferring energy to, the pigtail spring member 29 and is opening a gap at the interface 52.

After a brief period of ballistic flight, the hammers printing end insert 41 comes into contact with the paper I5] and the ribbon I50 (which are shown in FIG. 3) and accelerates these members toward the movable print font I52. Before the hammer printing insert 41 brings the ribbon and the paper and the print font into firm pressured contact, the hammer members penetration control stop engaging face 32 engages an energy-absorbing jacket 45, which surrounds the end of the penetration control adjustment arm 44.

Under influence of l the engaged penetration control stop face 32 with the jacket 45; and (2) contact between the hammer member 28 and the ribbon-paper-type-font array; and (3) the stretched pigtail spring member 29, motion of the hammer member 28 is arrested, so that the hammer 28 goes through an instant of zero velocity. The energy-absorbing jacket 45, which surrounds a portion of the penetration control arm 44, represents an embodiment of the first of five coordinated energyabso'rbing means which the present invention discloses.

In the prior art concerning high-speed printing mechanisms, it has been common practice to employ a penetration control stop member for limiting the travel of a hammer member into the paper and typefont of a printer; however, it has not been common to regard the penetration control as a means for extracting kinetic energy from the moving hammer member and to fabricate the penetration control with a structure which enhances its ability to extract kinetic energy.

By placing an energy-absorbing means, such as the jacket 45, within the penetration control assembly, it has been found possible to extract a significant quantity of kinetic energy from the moving hammer member 28 at a time when energy is no longer needed for the printing operation. To extract this kinetic energy, it is desirable that the stop jacket 45 be composed of a material which is sufficiently hard and dimensionally stable to afford a predictable limit of travel for the hammer member 28 while yet having a degree of resilience and elasticity which permit deflection under impact and thereby absorption of energy from the hammer member. In practice, it has been found possible to obtain a coefficient of restitution (a term expressing the ratio of rebound velocity to impact velocity) near 0.7 for the impact of the hammer member 28 with the typeline and paper and penetration control stop in the embodiment shown in FIG. I of the drawings. A detailed description of materials usable in fabricating the penetration control stop jacket 45 is given in a later section of this disclosure.

In addition to the jacket 45 and the stop arm 44, the penetration control stop assembly 55 of FIG. I is also provided with an adjustable mounting which consists of a pivot 47 and an adjusting member 51 connected to a frame portion of the printer and having a threaded end portion which engages the stop arm 44 at 48. Since the stop arm 44 is not called upon to make large adjustments in the position of the jacket 45 but is required to have high rigidity upon impact, the distance between the pivot point 47 and the impact jacket 45 is made small on the adjustment arm. The combination of energy absorption and high resolution position adjustment capability in the penetration stop assembly 55 represents a departure from normal high-speed printer practice; in many embodiments, it has been found difficult to provide the combined features of stop member rigidity, energy absorption capability, and easily changeable high resolution adjustment in a single assembly, as is illustrated in the FIG. I embodiment.

A second of the five coordinated energy-absorbing means disclosed in the present invention pertains to energy stored in the cantilever spring members 31 by virtue of their being masses moving at a high velocity (a velocity near 200 inches per second is possible in the FIG. 1 mechanism).

In many prior art printer mechanisms, it has been possible to dissipate kinetic energy from the cantilever hammer support springs by simply allowing the springs to flex or oscillate until energy is removed by spring heating or by windage or other naturally occurring dissipation mechanisms. In the printer mechanism of FIG. 1, where long operating life and quick hammer operation are desired and where operating energy levels are near 200,000 ergs, it is desirable to dissipate this cantilever spring energy in a manner which is more positive, involves less flexing of the springs, and can be accomplished more quickly.

To realize maximum life from the cantilever spring members 31, it is necessary that they not be forced into a curvature having abrupt changes in slope; flexing of the spring material is severe and concentrated into a small region of the spring when the spring enters and leaves an abrupt slope change configuration.

If the cantilever springs 31 are to avoid being forced into a curve having abrupt slope changes when the hammer member 28 and the spring members 31 have their forward motion arrested, it is necessary to recognize that the spring mass itself can retain sufficient kinetic energy to introduce a catenary curve (having abrupt changes of slope at each end) into the spring if movement of the hammer is arrested without corresponding arrest of spring motion.

In keeping with this premise, the present invention provides energy-absorbing members for arresting motion of the cantilever springs during the time hammer motion is being arrested. In FIG. 1, these energy-absorbing members are identified by the numerals 33 and 39. These energy-absorbing members function to both restrict the slope of the curvature into which the springs 31 conform and also extract kinetic energy from them, so that any period of oscillatory flexing by the springs is shortened.

Since it is not harmful for the cantilever springs 31 to periodically assume a configuration free of abrupt slope changes, the configuration of the energy-absorbing members 33 and 39 may be according to any one of several shapes. In the illustrated embodiment, it is found practical to employ a flat configuration for the energy-absorbing members 33 and, in addition, employ the concept of preloading the cantilever springs into a slightly nonstraight configuration while the hammer member 28 is at rest against the backstop assembly 24. With such an arrangement, the springs 31 may move into a straight configuration conforming with the straight energy-absorbing member shape upon excitation of the hammer member 28. The technique of employing nonstraight spring configuration while the hammer member 28 is at rest and straight configuration while it is being arrested permits the energy-absorbing members 33 and 39 to have a simple plane surface shape rather than a complex surface, which would require a more involved fabrication process. The incorporation of spring-energy-absorbing members has been found to have secondary benefits on the printer mechanism operation in addition to the primary benefits of precluding large bending loads on the spring, providing longer spring life, and providing reduced oscillation in the spring. It has been found that improved removal of kinetic energy from the springs during reversal of the print hammer's travel also permits motion of the hammer to be reversed more quickly following impact of the hammer and the print line and also contributes toward bringing the hammer mechanism to complete rest more quickly following the print operation.

In introducing the cantilever spring stop members 33 and 39, motion of the hammer assembly was considered up to the point where hammer impact with the typeline and the-penetration stop occurs and hammer motion is thereby arrested. Following the arresting of motion in the hammer member 28, ac-

celeration of the hammer member 28 away from the ribbon and paper area commences. This acceleration is induced by a combination of forces derived from (I) the stretched pigtail spring member 29, (2) compression in the resilient hammer body 28, (3) compression in the resilient cantilever spring stop members 33 and 39, (4) compressive deformation of the stop member jacket 45, and (5) resilient deformation in the typeline and stop members.

Although the jacket 45 placed over the stop arms impacting face serves primarily as an energy-dissipating medium, it does permit some of the kinetic energy with which the hammer member 28 strikes the jacket to be returned to the hammer member 28, so that compressive deformation of the stop member jacket is a significant return force and to be included in the foregoing list.

A spring coefficient near 25 pounds of force per inch of deflection has been found desirable for the pigtail spring 29 in addition to an initial or preset force for the FIG. 1 mechanism.

In FIG. 4 of the drawings, there is shown a representation of the solenoid electrical windings 138, having terminals 137, which are connected to terminals 136 of an exciting circuit. (In FIG. 4, the two electrical coils of FIG. 1 are shown combined into a single coil having but two terminals.)

In the solenoid-exciting circuit, the terminal designates a source of electrical energy having, in the embodiment shown, a positive potential with respect to ground. The numeral 131 in FIG. 4 designates an electronic device having the capability of controlling energy flow in the solenoid circuit. In practice, a variety of devices, such as a silicon controlled rectifier, a thyratron, or even a mechanical switch, may serve as the current control element at 131; the transistor shown in the FIG. 4 circuit may be operated either in the saturated switching mode or in the linear region of its curves to accomplish the current control function.

Also shown in FIG. 4 is a driving circuit 145, which converts an input signal received at the terminal 123 into a form acceptable by the control element 131.

Near the time that forward motion is arrested in the hammer member 28 and reverse motion of the hammer begins, the electronic switch 131, which controls current flow in the electrical coil of the solenoid assembly 54, is caused to open and remove power from the electrical coils. Since the coils are inductive in nature and are in a circuit shunted by a conductive path, 133 and 134, current continues to flow in the coils after power removal but begins to decrease in magnitude at the instant of power removal and as energy is extracted from the system. At some time after the flow of energy into the electrical coil is interrupted by the switch member 131, cur rent in the solenoid windings will have fallen to a value sufficiently low to permit the solenoid armature 20 to leave its closed position of contacting the solenoid yoke.

In the present invention, it has been found desirable to return the hammer member 28 to contact with the armature arm 17 (at the interface 52) after release of the solenoid armature from the solenoid yoke has occurred, rather than before release of the armature occurs. This mode of operation has been found to provide small hammer rebound. It is conceivable that other operation of the FIG. I mechanism is possible; operation wherein the hammer member 28 is returned to armature-arm-I7 contact before release of the armature 20 by the solenoid yoke, or operation wherein return of the hammer member 28 to the armature arm 17 provides the force which initiates release of the armature 20 by the solenoid yoke, is possible. It is intended that all of these possible return sequences come within the scope of this invention.

In FIG. 2, motion of the FIG. 1 printer hammer member 28 is plotted on a graph having hammer displacement as its vertical axis, and elapsed time as its horizontal axis, when the hammer is operated in the preferred mode outlined above, In the FIG. 2 graph, the numeral 116 represents the instant where power was first applied to the electrical coil of the solenoid assembly. Moving to the right along the horizontal, or time, axis of the FIG. 2 graph, the symbol 117 is used to indicate the time the axis is compressed and not to scale between the time of power application at 116 and the commencement of hammer member 28 motion which occurs at I 18.

In FIG. 2, the events already described, acceleration of the hammer member 28 toward the typeline and the paper, are described by the region 110 of the curve, starting at 118 and terminating at 111, when impact of the hammer member 28 occurs.

Following hammer impact at 111 in FIG. 2, the hammer member 28 is accelerated by the conglomerate of five forces, in the manner already disclosed above, back toward contact with the armature arm 17. During this time, the space at the interface 52 in FIG. 1 is being closed. This action is described by the portion of the curve in FIG. 2 between the numerals ll 1 and 112.

At the point 112 in FIG. 2, the space at 52 between the hammer member 28 and the armature arm 17 has been closed, and the hammer member 28 has come into contact with the armature arm 17, which was itself already relaxing back toward the backstop assembly 24.

As shown by the curve in FIG. 2, when the retreating hammer member 28 contacts the retreating armature arm 17, the direction of travel of the hammer member 28 is reversed, and a rebound having its peak at 113 in the curve occurs.

The third of five coordinated energy-dissipating means of this disclosure becomes effective in the events occurring at 112 and the following regions of the FIG. 2 curve. In this region, the armature boot member 22 provides an impact energy absorption means which helps dissipate energy that would otherwise appear as prolonged bouncing at point 112 of the curve.

Following the contact of the hammer member 28 with the retreating armature arm 17 and boot member 22 at 112 in the FIG. 2 curve, the hammer member 28 rebounds back toward the paper in a motion having its peak at 113 of the curve. A plurality of forces act upon the hammer member 28 to induce the motion occurring around the peak 113; these forces originate from some combination of the following:

1. elastic stretching in the armature arm 17 in FIG. 1;

2. elastic stretching in the armature arm boot member 22;

3. elastic stretching in the resilient hammer member 28;

4. elasticity in the magnetic coupling between the solenoid armature and the solenoid stator.

Although the exact sequence of events and behavior of the hammer 28 and the armature arm 17 in the 112-113 region is complex and subject to elaborate interpretation, several general traits of this behavior can be stated with affirmity:

It is known, for example, that the natural frequency of the events occurring at 112 and 113 in the cycle is close to the natural frequency of the armature arm 17 in FIG. 1. This similarity of natural frequencies suggests that elastic stretching within the armature arm 17 is a paramount influence on the events at 112 and 113 and that both the armature arm 17 and the hammer 28 move in a path described by the peak 113 following impact.

As previously indicated, termination of current flow in the control transistor 131 occurs at a time early enough to insure that the solenoid armature is not yet magnetically held to the solenoid yoke, when the hammer 28 contacts the armature arm 17, in the present embodiment; that is, the solenoid has commenced opening by the time event 112 occurs. This sequence has been found desirable in order that a large rebound peak at 113 may be prevented.

it is also known that the laws of momentum conservation apply to define the armature velocity after hammer contact at 112 in terms of armature velocity before hammer contact.

It is also known that the slope of the velocity curve in the region between 111 and 112 differs from that in the region 114 of the curve. Part of this slope difference results from viscous extraction of kinetic energy from the hammer-armature-arm system during the interval 114, as explained below.

Mathematical analysis of the events occurring at 112 in FIG. 2 shows that some bouncing of the hammer member 28 off of the retreating armature arm member 17 is to be expected in view of the forces and the elastic properties present. This bouncing off of the armature arm 17 is to be contrasted with rebounding in conjunction with the armature arm 17, which was explained above, and is distinguished from the rebounding by the bouncings having a higher frequency than the rebounding. This bouncing is mathematically predicted to occur a plurality of times during the time the hammer motion describes the secondary peak 113 in FIG. 2; that is, the home ing appears as ripples on the curve near the peak 113. In laboratory study of the action of the hammer member 28, there is some evidence of the presence of this bouncing; however, the amplitude is quite small with respect to the peak I 13, and for this reason the bouncing ripples are not shown in FIG. 2.

It is believed that energy-absorbing capability of the armature arm boot 22 in FIG. 1 is great enough to reduce the predicted high-frequency bouncing of the hammer member 28 or the armature arm 17 to a value which is barely perceptible with the most elaborate laboratory instrumentation that can be devised, in the FIGv 1 mechanism.

The concept of returning the hammer member 28 to contact with the retreating solenoid armature arm 17 and extracting kinetic energy from the system upon contact of the hammer member 28 with the armature arm 17 is a departure from conventional printer practice. In the present printer embodiment, one function of the pigtail spring member 29 and its unique location between the hammer member 28 and the armature arm 17 is to facilitate this extraction of kinetic energy.

In fabricating the boot member 22 for the armature arm, it is desirable to employ a material which is capable of dissipating kinetic energy upon being impacted and which provides dimensional stability in a fashion similar to the material used for the jacket 45, located on the penetration stop arm 44. It is found that a material which is of the same family as that used for the penetration stop jacket 45 is satisfactory for the armature arm boot 22. Use of exactly the same material is precluded by the different loading, which includes frictional rubbing in the case of the armature arm boot 22. An example of a material composition which has been found satisfactory for the armature arm boot 22 is given in a later section of this disclosure.

Following the impact of the hammer member 28 upon the retreating solenoid armature arm 17, the fourth of the five coordinated energy-absorbing means becomes important in describing mechanism behavior. This fourth of the five coordinated energy-dissipating means concerns energy which is electrically transmitted to a dissipation device by way of magnetic coupling between moving and stationary members within some magnetic transducing apparatus in the FIG. 1 mechanism. The important elements of this fourth energy-dissipating means are shown in FIG. 4 of the drawings for one embodiment of a magnetically coupled transdueing and dissipating apparatus.

Not only may the previously mentioned network, comprising the diode 134 and the electrical resistance 133 in FIG. 4, serve to maintain solenoid current after opening of the control 'element 131 and to limit solenoid voltage upon opening of the control element 131 in the FIG. 1 mechanism, as is common in the prior art, but in the present invention these elements may also extract kinetic energy from moving members of the hammer mechanism. This extraction of kinetic energy occurs by way of the maintained magnetic flux which couples the moving solenoid armature 20 with the stationary solenoid yoke. In the present invention, magnetic flux within the solenoid coil is maintained during the return of the solenoid armature arm 17 to its home position, in order that kinetic energy may be extracted from the system magnetically.

Other forms of magnetic coupling may be employed to extract kinetic energy from moving members of the FIG. 1 mechanism in lieu of magnetic coupling between the solenoid armature and the yoke which is employed in the FIG. 1 embodiment; for instance. the use of a permanent magnet and a coil attached directly to the armature arm 17 is entirely feasible. A coil which is suitable for this purpose may be formed from a solid piece of metal attached to the armature arm; in such an embodiment, movement of the solid metal member within a magnetic field produces Eddy currents in the metal member; these Eddy currents serve to extract kinetic energy from the moving members by way of heating the metal member.

Magnetically coupled energy absorption components in FIG. 1 provide for kinetic energy extraction which is viscous in nature; that is, the rate of energy dissipation is proportional to the velocity of the moving member in a manner similar to the extraction process which occurs from moving an object in a viscous fluid. In describing this invention, it is, of course,

recognized that a viscous energy absorption mechanism was already active upon the moving hammer and armature arm members before the electrical dissipation was added. This already-acting mechanism, that of windage or air resistance, is not considered a part of the present invention.

In the FIG. 1 mechanism, the rate at which energy is removed from the solenoid coils and hence from the moving hammer and armature arm members 28 and 17 in the viscous electrical dissipating system may be adjusted by changing the value of the resistance 133; a low value at 133 providing a slow rate of retreat for the armature arm 17 and a slow rate of energy absorption, while a high value provides more rapid retreat and faster energy absorption. The well-known rules governing behavior of current in an inductive circuit apply to the solenoid and energy-dissipating resistance if it is considered that both current and inductance are variable quantities.

An upper limit for the value of the resistance 133 is imposed by the necessity of maintaining the existence of magnetic flux within the solenoid 54 until the armature arm 17 has fully relaxed into its quiescent positionv If an excessively large value of resistance is employed at 133, the magnetic flux in the solenoid 54 will collapse rapidly upon opening of the control element 131, and no magnetic coupling between the solenoid armature 20 and the solenoid yoke will remain; without magnetic flux coupling between the solenoid armature and the solenoid yoke, energy could not be extracted electrically from the print hammer 28; to extract kinetic energy from the print hammer 28 electrically. the magnetic flux within the solenoid 54 must be maintained during the relaxation of the hammer and the armature arm into quiescent rest position. Premature total collapse of the magnetic field within the solenoid 54 would result in only the magnetic fields energy being dissipated at the resistance 133.

The extraction of kinetic energy from a moving hammer member by way of an electrical resistance has several advantages over conventional practice; among these advantages are:

1. Efficient extraction of the energy; that is, the coupling between the moving hammer member 28 and the electrical resistance 133 is quite effective;

2. The energy extraction occurs in a member (resistance 133) which is not harmed by energy dissipation. This is in contrast with the prior art mechanisms, which depend upon mechanical impact or elastic stretching of mechanism members to dissipate energy in the form of heat. In those mechanisms, the operating life of some mechanism component is often shortened by the energy-dissipating duty which it performs;

3. The energy extracted from the hammer member 28 may be conducted to the atmosphere at a selected and convenient point in the printer equipment, at a point remote from the hammer member 28 and the solenoid, where crowding and poor ventilation usually prevail;

4. A simple diode such as 134 may be employed to disable the extraction mechanism during excitation of the mechanism; by way of the diode 134, the dissipation mechanism does not deter from actuation performance ofthe printing mechanism.

It is informative to consider possible behavior of the printer components in the region 111 and 113 of the FIG. 2 curve if improper event sequence and ineffective energy absorption are employed in the mechanism. A person skilled in the highspeed printer art will recognize that the rebound peak at 113 in FIG. 2 represents a potential source of ghost printing from secondary impacting of the hammer member 28 with the typefont after the typefont has moved to a new position. If the amplitude of the peak 113 should increase to a larger value, ghost printing becomes a definite possibility. In relation to parameters of the printing mechanism and the energyabsorbing array, if the current in the solenoid 54 is maintained at a high value for a time extending past impact of the hammer member 28 with the armature arm 17, a greater rebound amplitude at 113 will result in the FIG. 1 mechanism; it is also true that, if the resilient energy-absorbing boot 22 is removed from the armature arm 17, or if the energy-absorbing boot 22 is less efficient in absorbing energy from the impending hammer member 28, a higher rebound peak will occur at 113 in FIG. 2.

During the time interval identified as 114 in FIG. 2, it is desired to quickly remove as much energy from the moving members as possible, in order that the printer may be ready for new printing cycle quickly. In the present embodiment, two modes of energy dissipation are active during this period-the viscous electrical system, culminating in heat dissipation by electrical resistance 133, as described above; and a second mode, resulting from dissipation from frictional sliding between the members 22 and 42 at the hammer-member-toarmature-arm interface 52.

During the early part of the interval 114, when velocity of the moving members is relatively high, the viscous electrical dissipating system is effective to remove kinetic energy from the moving parts. As velocity of the moving parts decreases, however, the coupling between the moving parts and the electrical resistance via the solenoids magnetic field decreases, so that effectiveness of the viscous electrical system decreases.

During the period of high velocity in the region 114 and down to zero velocity, the frictional energy-dissipating system which operates at the interface 52 between the hammer member 28 and the armature arm 17 is effective to remove energy from the moving parts. The effectiveness of this frictional sliding as a dissipation means may be understood by realizing that the center of rotation about which the armature arm 17 moves is located at the solenoid pivot 43 in FIG. 1. Since the hammer member 28 moves in a straight line in a vertical plane and the armature arm boot member 22 moves along a path defining the circumference of a circle having its center at the pivot 43, it is clear that frictional sliding occurs at the interface 52in FIG. 1.

It is also to be recalled that the frictional sliding at the interface 52 occurs while the members 22 and 42 are urged together by force from the pigtail spring 29. As was mentioned above, the pigtail spring 29 provides a preset force which is effective to urge the hammer member 28 and the armature arm 17 into contact with each other.

Since the pigtail spring 29 in FIG. 1 performs functions in addition to providing frictional normal force across the interface 52, it is not possible to elect the frictional normal force with complete freedom. In the illustrated embodiment of the invention, a small preset force is provided for energy dissipation from the frictional members.

For identification purposes, the frictional sliding energy dissipation at the interface 52 is considered to be a part of the third of the five coordinated energy dissipation means disclosed in this specification. Previously, the impact between the hammer member 28 and the armature arm 17 at the interface 52 was identified as the third of the five coordinated energy dissipation means; although it is clear that the frictional sliding and the impact event are two separate dissipation mechanisms, the occurrence of both at the interface 52 suggests that they be combined for identification purposes in this description. The viscous electrical energy dissipation is the fourth of the five energy dissipation means.

Following the period of energy dissipation from the electrical resistance and the frictional surfaces in the region 114 of FIG. 2, some energy remains in the moving mechanism members; that is, they are moving at the same finite velocity. Dissipation of the kinetic energy represented by this finite velocity is the province of the fifth of the five coordinated energy dissipating means.

The fifth of the energy-dissipating means is embodied in the mechanism of FIG. I in the form of a portion of the armature arm boot 22 which strikes the backstop assembly 24 upon the return of the armature arm 17 and the hammer member 28 to the home position.

It will be appreciated by a person skilled in the art that the quantity of energy to be absorbed in the backstop impact is a compromise; that is, the velocity of the hammer member 28 when it approaches the backstop assembly 24 can be relatively low or relatively high, depending upon the amount of hammer kinetic energy absorbed by the four previously named energydissipating means, and in particular depending upon the time allocated to absorption through the viscous electrical dissipation means.

In practice, it is found desirable to tolerate a moderate period of rebounding when the moving members strike the backstop; that is, for the viscous electrical dissipating system and the frictional dissipating system to permit the moving members to reach the backstop with a velocity sufficiently high to induce moderate rebounding. This condition is depicted in FIG. 2, where the damped sinusoid at 115 represents the rebounding period.

The backstop member against which the rebounding at 115 in FIG. 2 occurs is shown cut away in FIG. 1, so that its internal structure may be viewed; in this view, the cutting line reveals that the backstop is composed of a solid member 25 mounted upon a threaded adjustment member 26, the entire assembly being held in position by a rigid support member 27.

The body portion 25 of the backstop member is composed of molded nylon or similar plastic material. It is intended that this body offer immunity to the repeated impacting of the armature arm 17 as a primary capability and, as a secondary function, offer energy absorption capability. Primary energy absorption capability in the backstop member is vested in the armature arm boot member 22, however.

Material used for the portion of the boot 22 which impacts with the body portion 25 of the backstop member has been found suitable for use in the portion of the boot which impacts with and frictionally contacts the hammer member 28 at the interface 52 in the illustrated embodiment of the invention. This material is suitable for frictional contact between the hammer member 28 and the armature arm 17 primarily because the hammer members driving insert 41 is fabricated from a material having lubricating properties, such as an acetal filled with Teflon fibers. Tefion is a trademark of E. i. du Pont de Nemours and Company.

It will be appreciated by a person skilled in the art that the selection of materials for the armature arm boot 22 and the contacting member 25 of the backstop assembly 24 involves a compromise between materials which are, on one hand, relatively hard and capable of precisely defining the home position of the armature arm hammer assembly and thereby ahsorbing energy at a rate slow enough to result in some bouncing of the armature arm 17 (as shown at 115 in FIG. 2), and on the other hand selecting materials which are resilient enough and dissipative in nature so as to decrease the bounce tendency but provide nonprecise location of the armature arms quiescent home position.

in fabricating members of the printing mechanism shown in FIG. 1 of the drawings, it has been found desirable to employ materials which are not conventional in the art of printing mechanisms. In the following paragraphs, the materials employed in portions of the mechanism involved with the energydissipating system are disclosed.

For the embodiment shown in FIG. 1 of the drawings, it has been found desirable to fabricate the hammer member 28 with the body portion composed of nylon containing 40 percent glass fibers as a filler, and to employ a powdered metal insert at the hammers impacting end 41. At the driven end of the hammer member 28, an insert member 42 provides resistance to impact loading while also providing a lubricative surface for frictional engagement by the hammer-driving arm 17.

It has been found that the driven end insert member 42 is most conveniently fabricated from a composite material having a base or vehicle portion, providing the desired dimensional stability and impact properties, and a filler or dispersed portion, which provides the lubricative properties. For this purpose, a material having a base composition of acetal. such as Delrin, and a filler composed of material such as Teflon has been found acceptable. A specific material found satisfactory in the insert member 42 is designated Delrin A. F." by its manufacturer, E. I. du Pont de Nemours and Company; it is composed of Delrin acetal having 14 percent Teflon fibers as a filler. This material may be fabricated by molding. Delrin" and Teflon" are trademarks of E. I. du Pont de Nemours and Company.

In the prior art, it has been common to employ materials such as cork or butyl rubber in the fabrication of energy-absorbing impact members similar to the cantilever spring engaging pads 33 and 39 in F 1G. I. In the illustrated embodiment of a printer, these materials were found to be inferior to a pad composition composed of soft neoprene rubber; neoprene rubber having a hardness near H) on the Shore A scale of a durometer. It has been found that neoprene rubber of this hardness offers a desirable compromise between the functions of energy absorption and impactable support for the cantilever springs 31.

Neoprene rubber was found to have more desirable properties for this impact-absorption application than butyl rubber or foams of vinyl, polyurethane, or polyethylene. The neoprene rubber energy-absorbing members are mounted with adhesive on adjacent rigid portions of the printer mechanism frame in the illustrated embodiment.

The material selected for the energy-dissipative impact face member of the penetration stop, the member 45 in the embodiment of FIG. 1, is required to have the combined properties of impact resistance, dimensional stability, energy absorption, and ease of fabrication. Several families of materials have been found to have desirable combinations of these properties, but none exceeds material from the urethane family in overall performance.

Within the urethane family, it was found that great variation is experienced for the different materials in the impact loading environment of the face member 45 of the penetration stop assembly 55. For instance, many of the common urethane materials failed after an operating life of less than 30 million cycles in the stop environment. A particularly troublesome failure of many materials in this service is gaseous decomposition induced by heat buildup and high temperature decom position within the urethane structure during repeated highduty cycle loading. To overcome this failure, it is desirable to employ a material whose temperature modulus profile exhibits a relatively long flat region. The temperature modulus profile graphically relates the modulus or resilience of the material as plotted on a vertical axis to the temperature of the material as plotted on a horizontal axis. A material having a relatively long flat temperature modulus profile has a modulus value which is nearly constant over a wide range of temperatures. For example, temperature modulus curves which are relatively flat between the temperature of IO C. and 160 C. are commonly available.

One material which was found to provide satisfactory service in the hammer stop environment is a polyester polyurethane manufactured by American Cyanamid Corporation. This material is identified as a polyester polyurethane containing 4.0 to 4.3 percent free isocyanate; for this use, it is cured with a 25 to 75 percent combination of dichlorobenzidine and methylene bis(ortho-chloroaniline) at percent stoichiornetry.

Although a material identical to that recited above for the penetration stop face member 45 provides partially satisfactory performance in the environment of the hammer armature arm boot 22 in H6. 1, it is found that the different loading conditions imposed upon the armature arm boot 22 dictate that another material be used for this member. it is noted that the armature arm boot member 22, in addition to encountering impact loading similar to the face member 45 of the penetration stop assembly 55, also incurs frictional rubbing contact with the end surface of the hammer member at the interface 52.

One material which has been found satisfactory for use in the armature arm boot 22 is a Cyanaprene D5 polymer manufactured by American Cyanamid Corporation. in using this polymer, a curative, Cyanaset-H, a blend of dichlorobenzidine and methylene bis(ortho-chloroaniline), is employed with a stoichiometry of 100 percent. The curative Cyanaset-H is also manufactured by American Cyanamid Corporation.

In fabricating the boot member 22 from the Cyanaprene and Cyanaset materials, transfer molding apparatus is employed along with heated molding dies; demolding of the boot member 22 may occur after an initial curing in the mold of about l minutes duration at 212 F. Following demolding of the parts, a postcure of 16 hours at 212 F. is also employed.

In accomplishing the urethane-to-metal bond for both the armature arm boot 22 and the face member 45 of the penetration stop assembly 55, it has been found desirable to employ a urethane bonding agent such as one manufactured by Dayton Chemical Laboratories, Incorporated, of West Alexandria, Ohio, United States of America, and sold under the designation Thixon XAB-936. Thixon" is a trademark of the foregoing company.

What is claimed is:

1. In a mechanism having a small working member that is mounted to be freely movable along an axis into engagement with a work portion and rebound thereafter, and which has said working member ballistically propelled into said work portion by engagement of an external exciting member with said working member,

resilient means connected between said working member and said exciting member and operable to reengage said working member with said external exciting member upon rebound of said working member following engagement with said work portion and while said external exciting member is yet displaced from a quiescent position from having propelled said working member,

magnetic coupling and transducing apparatus mechanically connected with said external exciting member and electrically connected to an electrical network, said apparatus acting upon said external exciting member while said member is traveling toward said quiescent position from said displaced position and transducing kinetic energy possessed by said external exciting member and said working member into electrical energy, and

electrical dissipating means coupled electrically with said magnetic coupling and transducing apparatus,

whereby kinetic energy is extracted from said moving working member by returning said working member to engagement with said exciting member and electrically dissipat ing energy from the moving combination of working member and exciting member.

2. In a high-speed printing mechanism of the type having a small lightweight printing hammer member which is mounted in connection with a frame member so as to be freely movable along one axis of said hammer member and which is energized by a rapidly moving external exciting member which contacts said printing hammer member near an end of said printing hammer member,

first resilient means connected to said printing hammer member and said external exciting member for reengaging said printing hammer member with said external exciting member following printing impact by said hammer member and while said exciting member is yet displaced as a result of having excited said hammer member,

second resilient means connected to said external exciting member and said frame member for aiding return of said rcengaged external exciting member and hammer member to a quiescent home position,

magnetoelectric transducing and coupling means mounted upon said frame member and coupled magnetically with said exciting member for transducing kinetic energy from said exciting member and said printing hammer member into electrical energy, and

electrical dissipating means externally located from said magnetoelectric transducing and coupling means and electrically connected with said magnetoelectric transducing and coupling means so as to electrically dissipate energy from said external exciting member and said printing hammer member.

3. The combination ofclaim 2 wherein said magnetoelectric transducing and coupling means comprises an electrical solenoid, and

said electrical solenoid is the same solenoid as that which excites said exciting member of said mechanism.

4. The combination of claim 3 wherein said exciting member comprises an exciting arm which is pivotally mounted and connected with an armature portion of said solenoid at one end thereof and engages said hammer member at the other end thereof, and

said first resilient means comprises a spring member which is permanently attached to said printing hammer member and removably attached to said external exciting member.

5. A high-speed printer mechanism comprising:

a mechanism support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imparting printed information to impacted media;

drivable hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

a stop member connected to said frame member in a rigid manner and so located with respect to said drivable hammer member as to be engaged by said hammer stopmember-engaging portion when said hammer member is in engagement with said type font array, whereby kinetic energy from said hammer member is transferred largely to said stop member and said type font array;

a forward cantilever flexure spring attached to said frame member and to said hammer member in a supporting manner;

a rearward cantilever flexure spring attached to said frame member and to said hammer member in a supporting manner;

excitation means capable of energizing said hammer member into motion along said longitudinal axis;

a first energy-absorbing member mounted in a position wherein engagement with a large central portion of said forward cantilever flexure spring occurs when said hammer member engages said type font array; and

a second energy-absorbing member mounted in a position wherein engagement with a large central portion of said rearward cantilever flexure spring occurs when said hammer member engages said type font array, said first and second energy-absorbing members being composed of resilient organic material configured into padlike members of a size at least equal to a substantial fraction of said flexure springs size and mounted in connection with said frame member,

whereby movement of said hammer member is halted and 70 reversed by said type font array and said hammer-engaged stop member, and said energy-absorbing members are capable of quickly arresting motion in said forward and rearward cantilever springs and extracting kinetic energy from said springs without subjecting said springs to large life-reducing flexure stresses.

6. A high-speed printer mechanism as in claim wherein said padlike members are configured into a shape having a flat surface engageable by said flexure springs, and

said printer mechanism includes means for holding said flexure springs in a nonstraight and slightly cocked position while said hammer member rests in a quiescent home position, and

said padlike members are mounted at an acute angle with respect to the general locus of said nonstraight slightly cocked spring position, said acute angle having its vertex near the point where said flexure springs attached to said frame member,

whereby said flexure springs move from said nonstraight slightly cocked position into a nearly straight position engaging said padlike members as a result of said hammer member's being excited.

7. A high-speed printer mechanism as in claim 5 wherein said padlike members are composed of neoprene rubber having a hardness near on the Shore A durometer scale.

"g. A high-speed printing mechanism comprising:

a stationarily mounted support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium;

a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member;

a hammer stop member connected to said frame member and so located with respect to said drivable ballistic hammer as to be engaged by said hammer stop-memberengaging portion when said hammer member is in engagement with said type font array;

excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism s operating cycle;

a backstop member on said frame member and so located as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; resilient kinetic-energy-absorbing members mounted on said frame member in a position wherein engagement with each of said flexure support springs will occur when said hammer member engages said type font; a resilient kinetic-energy-dissipative face member, mounted on the hammer-engaging face of said hammer stop member, which is contacted by said hammer-stopmember-engaging portion of said hammer member when said hammer member engages said type font array; energy-dissipative face members mounted upon mutuallycontacting surfaces of said hammer member and said actuating arm member, at least one of said face members being deformable with resistance upon impact so as to be dissipative of impact-imparted kinetic energy,

said face members being urged into contact during a large portion of said printing mechanisms operating cycle by resilient urging means operative upon at least one of said hammer and actuating arm members to both urge said members into contacting concerted movement with respect to said frame member and increase kinetic-energydissipating sliding friction between said members during relative movement at said mutually contacting surface;

magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means; and

a kinetic-energy-dissipative impact face member mounted upon at least one of the mutually contacting surfaces of said actuating arm member or said backstop member, said face member acting to dissipate kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position.

9 A high-speed printing mechanism as in claim 8 wherein said resilient kinetic-energy-absorbing members engageable by said flexure support springs are composed of neoprene rubber;

said energy-dissipative impact face member for said hammer stop member is composed of prepolymer polyester urethane material with curative and having a relatively long temperature modulus profile;

one of said dissipative face members mounted upon mutually contacting surfaces of said hammer member and said actuating arm member is composed of acetal material having a lubricative filler dispersed therein;

the other of said face members is composed of an elastomeric prepolymer polyester urethane material with curative and having a relatively long temperature modulus profile; and

said energy-dissipative impact face member engaged at said backstop and quiescent home positions is composed of an elastomeric prepolymer polyester urethane material with curative and having a relatively long temperature modulus profile.

10. A hi gh-speed printing mechanism comprising:

a stationarily mounted support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium;

a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member;

a hammer stop member connected to said frame member and so located with respect to said drivable ballistic hammer as to be engaged by said hammer-stop-memberengaging portion when said hammer member is in engagement with said type font array;

excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanisms operating cycle;

resilient urging means operative upon at least one of said hammer and said actuating arm members for urging said members into contacting concerted movement with respect to said frame member during portions of the operating cycle of said high-speed printing mechanism;

a backstop member on said frame member and so iocated as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members;

resilient kinetic-energy-absorbing members mounted on said frame member in a position wherein engagement with each of said flexure support springs will occur when said hammer member engages said type font; and

magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing meansv 11. A high-speed printing mechanism comprising:

a stationarily mounted support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium;

a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop member engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member;

a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer stop member engaging portion when said hammer member is in engagement with said type font array;

excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanisms operating cycle;

a backstop member on said frame member and located so as to be engaged by retreating motion of said actuating member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members;

a resilient kinetic energy dissipative face member mounted on the hammer-engaging face of said hammer stop member which is contacted by said hammer-stopmember-engaging portion of said hammer member when said hammer member engages said type font array; and

magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by a resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means.

12. A high-speed printing mechanism comprising:

a stationary mounted support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium;

a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop member engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member;

a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer-stop-member-engaging portion when said hammer member is in engagement with said type font array;

excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism's operating cycle;

a backstop member mounted on said frame member and located so as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members;

a resilient kinetic energy dissipative face member mounted on the hammer-engaging face of said hammer stop member which is contacted by said hammer-stopmember-engaging portion of said hammer member when said hammer member engages said type font array; and

kinetic energy dissipative impact face members mounted upon mutually contacting surfaces of each said actuating arm member and said backstop member, said face members dissipating kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position.

13. A high-speed printing mechanism comprising:

a stationary mounted support frame member;

a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium;

a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array;

forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member;

a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer-stop-member-engaging portion when said hammer member is in engagement with said type font array;

excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism's operating cycle;

a backstop member mounted on said frame member and located so as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; energy-dissipative face members mounted upon mutually contacting surfaces of said hammer member and said actuating arm member, at least one of said face members being deformable with resistance upon impact so as to be dissipative of impact imparted kinetic energy,

said face members being urged into contact during a large portion of said printing mechanism's operating cycle by resilient urging means operative upon at least one of said hammer and actuating arm members to both urge said members into contacting concerted movement with respect to said frame member and increase kinetic energy dissipating sliding friction between said members during relative movement at said mutually contacting surface; magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means; and kinetic energy dissipative impact face members mounted upon mutually contacting surfaces of each said actuating arm member and said backstop member, said face members dissipating kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position. 14. A method for operating a small working member in a mechanism, comprising the steps of:

accelerating said working member by engagement with a magnetically coupled accelerating member; decelerating said accelerating member while said accelerating member is in a displaced position; disengaging said working member from said accelerating member, thereby permitting said working member to travel alone into a working position; returning said working member to engagement with said displaced accelerating member following work performance by said working member in said working position; extracting a first quantity of kinetic energy from said working member upon reengagement with said accelerating member; restoring said engaged working member and accelerating member to a quiescent home position; removing a second quantity of kinetic energy from said working member during said restoring and after said reengagement between said accelerating member and said working member and by means of said magnetic coupling; and dissipating said second quantity of kinetic energy by way of an electrical current from said magnetic coupling flowing in a dissipating means. 15. A method for operating a lightweight impacting working member in a high speed mechanism comprising the steps of:

accelerating said working member forward toward work media while employing resilient means to hold said working member in engagement with an accelerating member; halting the forward motion of said accelerating member while in a displaced position while allowing said working member to continue in essentially free flight toward said work media and while stretching said resilient means; limiting the impact of said working member with said work media by engaging said working member with a kinetic energy absorbing stopping means; retracting said working member from contact with said work media and said stopping means with the aid of said stretched resilient means; returning said working member to engagement with said accelerating member; extracting kinetic energy from said working member upon engagement with said accelerating member; restoring said engaged accelerating member and working member to a quiescent home position while simultaneously removing kinetic energy therefrom; and withdrawing additional kinetic energy from said engaged members upon their return to said home position. v

16. A method for operating a print hammer in a high-speed printing mechanism and quickly bringing said hammer to quiescence after operation comprising the steps of:

accelerating said print hammer forward toward printable media to be imprinted while resiliently maintaining said print hammer in engagement with a magnetically coupled accelerating member; halting the forward motion of said accelerating member while in a displaced position from accelerating said print hammer and while said print hammer is continuing under propulsion by its own inertia toward said printable media;

limiting the impact of said print hammer with said printable media by concurrently engaging said hammer with kinetic energy absorbing resilient stopping means and said printable media;

resiliently retracting said print hammer from contact with said printable media and said stopping means;

returning said print hammer to engagement with said magnetically coupled accelerating member;

extracting kinetic energy from said print hammer upon its engagement with said magnetically coupled accelerating member;

restoring said engaged print hammer member and accelerating member to a quiescent home position while also removing kinetic energy from said members via said magnetic coupling; and

withdrawing additional kinetic energy from said engaged members upon their return to said quiescent home positionv l7. Energy-absorbing and excursion-limiting apparatus including a penetration stop member for a high-speed impact printing mechanism that also includes a print hammer member suspended from a frame member and movable along a lengthwise axis between a rest position and an extended position wherein engagement with both a printable medium and said energy-absorbing, excursion-limiting apparatus occurs, said energy-absorbing and excursion-limiting apparatus also including:

metallic position adjustment means for supporting and for providing vernier position adjustment of said penetration stop member, said metallic position adjustment means including a threaded metallic member connected with a force-multiplying, resolution-increasing lever of the first class, and

resilient organic material energy-absorbing means supported on said penetration stop member and positionlocated by said metallic position adjustment means for engaging said print hammer member near said extended position, reversing movement direction of said print hammer member, absorbing kinetic energy from said print hammer member and converting said kinetic energy into heat energy,

whereby said energy-absorbing and excursion-limiting apparatus provides a rigid and position-adjustable limit of travel for said print hammer member together with energy-dissipating means for said print hammer member.

18. Energy-absorbing and excursion-limiting apparatus as in claim 17 wherein said resilient organic material lenergy-absorbing means includes a thermoplastic material jacket member molded around an end portion of said penetration stop member.

19. Energy-absorbing and excursion-limiting apparatus as in claim 18 wherein the composition of said thermoplastic material jacket member includes a polyester polyurethane material having 4.0 to 4.3 percent isocyanate and cured with a 25 to 75 percent combination of dichlorobenzidine and methylene bis(ortho-chloroaniline) at percent stoichiometry.

20. Energy-absorbing and excursion-limiting apparatus for a high-speed impact printing mechanism that includes a print hammer suspended'by cantilever flexure springs from a frame member and movable along a lengthwise axis between a rest position and an extended position wherein engagement between said energy-absorbing and excursion-limiting apparatus and plural portions of said print hammer and flexure springs occurs; said energy-absorbing and excursion-limiting apparatus comprising:

plural first resilient energy-absorbing stop member means each larger than said cantilever flexure springs and each in rigid connection with said frame member adjacent each of said cantilever flexure springs for engaging a large portion of each of said cantilever flexure springs in said extended position and for removing kinetic energy from said cantilever flexure springs upon said springs approaching said extended position; and

second resilient energy-absorbing stop member means rigidly connected with said frame member adjacent said print hammer for engaging said print hammer in said extended position and for removing kinetic energy from said print hammer upon said print hammer approaching said extended position;

whereby separate energy-absorbing means members are provided for kinetic energy removal from said flexure springs and for kinetic energy removal from said print hammer and the severe flexing of said flexure springs by the rapid and bilateral transfer of kinetic energy between said print hammer and central portions of said flexure springs during impact of said print hammer at said extended position is minimized. 2l. Energy-absorbing and excursion-limiting apparatus as in claim 20 wherein said plural first resilient energy-absorbing stop member means includes a plurality of neoprene rubber energy-absorbing pad members, there being one pad member for each of said cantilever flexure-springs.

22. Energy-absorbing and excursion-limiting apparatus as in claim 21 wherein said neoprene rubber is a soft neoprene rubber having a hardness near l0 on the Shore A durometer scale and said pad members are substantially flat in configuration. 

1. In a mechanism having a small working member that is mounted to be freely movable along an axis into engagement with a work portion and rebound thereafter, and which has said working member ballistically propelled into said work portion by engagement of an external exciting member with said working member, resilient means connected between said working member and said exciting member and operable to reengage said working member with said external exciting member upon rebound of said working member following engagement with said work portion and while said external exciting member is yet displaced from a quiescent position from having propelled said working member, magnetic coupling and transducing apparatus mechanically connected with said external exciting member and electrically connected to an electrical network, said apparatus acting upon said external exciting member while said member is traveling toward said quiescent position from said displaced position and transducing kinetic energy possessed by said external exciting member and said working member into electrical energy, and electrical dissipating means coupled electrically with said magnetic coupling and transducing apparatus, whereby kinetic energy is extracted from said moving working member by returning said working member to engagement with said exciting member and electrically dissipating energy from the moving combination of working member and exciting member.
 2. In a high-speed printing mechanism of the type having a small lightweight printing hammer member which is mounted in connection with a frame member so as to be freely movable along one axis of said hammer member and which is energized by a rapidly moving external exciting member which contacts said printing hammer member near an end of said printing hammer member, first resilient means connected to said printing hammer member and said external exciting member for reengaging said printing hammer member with said external exciting member following printing impact by said hammer member and while said exciting member is yet displaced as a result of having excited said hammer member, second resilient means connected to said external exciting member and said frame member for aiding return of said reengaged external exciting member and hammer member to a quiescent home position, magnetoelectric transducing and coupling means mounted upon said frame member and coupled magnetically with said exciting member for transducing kinetic energy from said exciting member and said printing hammer member into electrical energy, and electrical dissipating means externally located from said magnEtoelectric transducing and coupling means and electrically connected with said magnetoelectric transducing and coupling means so as to electrically dissipate energy from said external exciting member and said printing hammer member.
 3. The combination of claim 2 wherein said magnetoelectric transducing and coupling means comprises an electrical solenoid, and said electrical solenoid is the same solenoid as that which excites said exciting member of said mechanism.
 4. The combination of claim 3 wherein said exciting member comprises an exciting arm which is pivotally mounted and connected with an armature portion of said solenoid at one end thereof and engages said hammer member at the other end thereof, and said first resilient means comprises a spring member which is permanently attached to said printing hammer member and removably attached to said external exciting member.
 5. A high-speed printer mechanism comprising: a mechanism support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imparting printed information to impacted media; a drivable hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; a stop member connected to said frame member in a rigid manner and so located with respect to said drivable hammer member as to be engaged by said hammer stop-member-engaging portion when said hammer member is in engagement with said type font array, whereby kinetic energy from said hammer member is transferred largely to said stop member and said type font array; a forward cantilever flexure spring attached to said frame member and to said hammer member in a supporting manner; a rearward cantilever flexure spring attached to said frame member and to said hammer member in a supporting manner; excitation means capable of energizing said hammer member into motion along said longitudinal axis; a first energy-absorbing member mounted in a position wherein engagement with a large central portion of said forward cantilever flexure spring occurs when said hammer member engages said type font array; and a second energy-absorbing member mounted in a position wherein engagement with a large central portion of said rearward cantilever flexure spring occurs when said hammer member engages said type font array, said first and second energy-absorbing members being composed of resilient organic material configured into padlike members of a size at least equal to a substantial fraction of said flexure springs'' size and mounted in connection with said frame member, whereby movement of said hammer member is halted and reversed by said type font array and said hammer-engaged stop member, and said energy-absorbing members are capable of quickly arresting motion in said forward and rearward cantilever springs and extracting kinetic energy from said springs without subjecting said springs to large life-reducing flexure stresses.
 6. A high-speed printer mechanism as in claim 5 wherein said padlike members are configured into a shape having a flat surface engageable by said flexure springs, and said printer mechanism includes means for holding said flexure springs in a nonstraight and slightly cocked position while said hammer member rests in a quiescent home position, and said padlike members are mounted at an acute angle with respect to the general locus of said nonstraight slightly cocked spring position, said acute angle having its vertex near the point where said flexure springs attached to said frame member, whereby said flexure springs move from said nonstraight slightly cocked position into a nearly straight position engaging said padlike members as a result of said hammer member''s being excited.
 7. A high-speed printer mechAnism as in claim 5 wherein said padlike members are composed of neoprene rubber having a hardness near 10 on the Shore A durometer scale.
 8. A high-speed printing mechanism comprising: a stationarily mounted support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium; a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member; a hammer stop member connected to said frame member and so located with respect to said drivable ballistic hammer as to be engaged by said hammer stop-member-engaging portion when said hammer member is in engagement with said type font array; excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism''s operating cycle; a backstop member on said frame member and so located as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; resilient kinetic-energy-absorbing members mounted on said frame member in a position wherein engagement with each of said flexure support springs will occur when said hammer member engages said type font; a resilient kinetic-energy-dissipative face member, mounted on the hammer-engaging face of said hammer stop member, which is contacted by said hammer-stop-member-engaging portion of said hammer member when said hammer member engages said type font array; energy-dissipative face members mounted upon mutually-contacting surfaces of said hammer member and said actuating arm member, at least one of said face members being deformable with resistance upon impact so as to be dissipative of impact-imparted kinetic energy, said face members being urged into contact during a large portion of said printing mechanism''s operating cycle by resilient urging means operative upon at least one of said hammer and actuating arm members to both urge said members into contacting concerted movement with respect to said frame member and increase kinetic-energy-dissipating sliding friction between said members during relative movement at said mutually contacting surface; magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means; and a kinetic-energy-dissipative impact face member mounted upon at least one of the mutually contacting surfaces of said actuating arm member or said backstop member, said face member acting to dissipate kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position.
 9. A high-speed printing mechanism as in claim 8 wherein said resilient kinetic-energy-absorbing members engageable by said flexure support springs are composed of neoprene rubber; said energy-dissipative impact face member for said hammer stop member is composed of prepolymEr polyester urethane material with curative and having a relatively long temperature modulus profile; one of said dissipative face members mounted upon mutually contacting surfaces of said hammer member and said actuating arm member is composed of acetal material having a lubricative filler dispersed therein; the other of said face members is composed of an elastomeric prepolymer polyester urethane material with curative and having a relatively long temperature modulus profile; and said energy-dissipative impact face member engaged at said backstop and quiescent home positions is composed of an elastomeric prepolymer polyester urethane material with curative and having a relatively long temperature modulus profile.
 10. A high-speed printing mechanism comprising: a stationarily mounted support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium; a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being so supported as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member; a hammer stop member connected to said frame member and so located with respect to said drivable ballistic hammer as to be engaged by said hammer-stop-member-engaging portion when said hammer member is in engagement with said type font array; excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism''s operating cycle; resilient urging means operative upon at least one of said hammer and said actuating arm members for urging said members into contacting concerted movement with respect to said frame member during portions of the operating cycle of said high-speed printing mechanism; a backstop member on said frame member and so located as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; resilient kinetic-energy-absorbing members mounted on said frame member in a position wherein engagement with each of said flexure support springs will occur when said hammer member engages said type font; and magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means.
 11. A high-speed printing mechanism comprising: a stationarily mounted support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium; a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop member engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to saId hammer member; a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer stop member engaging portion when said hammer member is in engagement with said type font array; excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism''s operating cycle; a backstop member on said frame member and located so as to be engaged by retreating motion of said actuating member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; a resilient kinetic energy dissipative face member mounted on the hammer-engaging face of said hammer stop member which is contacted by said hammer-stop-member-engaging portion of said hammer member when said hammer member engages said type font array; and magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by a resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means.
 12. A high-speed printing mechanism comprising: a stationary mounted support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium; a drivable ballistic hammer member for bringing media into contact with said type font array, said hammer member including a stop member engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member; a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer-stop-member-engaging portion when said hammer member is in engagement with said type font array; excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism''s operating cycle; a backstop member mounted on said frame member and located so as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; a resilient kinetic energy dissipative face member mounted on the hammer-engaging face of said hammer stop member which is contacted by said hammer-stop-member-engaging portion of said hammer member when said hammer member engages said type font array; and kinetic energy dissipative impact face members mounted upon mutually contacting surfaces of each said actuating arm member and said backstop member, said face members dissipating kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position.
 13. A high-speed printing mechanism comprising: a stationary mounted support frame member; a type font array which is movably mounted with respect to said frame member and is capable of imprinting character information on a medium upon contact with said medium; a drivable ballistic hammer member for bringing media into contaCt with said type font array, said hammer member including a stop-member-engaging portion integral therewith, said hammer member being supported so as to be freely movable along a longitudinal axis between a quiescent home position and a position engaging said type font array; forward and rearward cantilever flexure support springs for said hammer member, said springs being attached at one end thereof to said hammer member; a hammer stop member connected to said frame member and located with respect to said drivable ballistic hammer so as to be engaged by said hammer-stop-member-engaging portion when said hammer member is in engagement with said type font array; excitation means for energizing said hammer member into motion along said longitudinal axis by way of a pivotally mounted actuating arm member which engages an end portion of said hammer member during a large portion of said printing mechanism''s operating cycle; a backstop member mounted on said frame member and located so as to be engaged by retreating motion of said actuating arm member, said backstop member thereby being capable of determining the quiescent locus of said actuating arm and said print hammer members; energy-dissipative face members mounted upon mutually contacting surfaces of said hammer member and said actuating arm member, at least one of said face members being deformable with resistance upon impact so as to be dissipative of impact imparted kinetic energy, said face members being urged into contact during a large portion of said printing mechanism''s operating cycle by resilient urging means operative upon at least one of said hammer and actuating arm members to both urge said members into contacting concerted movement with respect to said frame member and increase kinetic energy dissipating sliding friction between said members during relative movement at said mutually contacting surface; magnetic coupling and transducing means coupled to said actuating arm member and activatable by external control means to extract kinetic energy from said actuating arm member and said hammer member as said members are urged into concerted movement by said resilient urging means, said extracted kinetic energy being converted into electrical energy by said magnetic coupling and transducing means and dissipated by an electrical network connected with said magnetic coupling and transducing means; and kinetic energy dissipative impact face members mounted upon mutually contacting surfaces of each said actuating arm member and said backstop member, said face members dissipating kinetic energy from said actuating arm member and said hammer member upon impact as said members reach said quiescent home position.
 14. A method for operating a small working member in a mechanism, comprising the steps of: accelerating said working member by engagement with a magnetically coupled accelerating member; decelerating said accelerating member while said accelerating member is in a displaced position; disengaging said working member from said accelerating member, thereby permitting said working member to travel alone into a working position; returning said working member to engagement with said displaced accelerating member following work performance by said working member in said working position; extracting a first quantity of kinetic energy from said working member upon reengagement with said accelerating member; restoring said engaged working member and accelerating member to a quiescent home position; removing a second quantity of kinetic energy from said working member during said restoring and after said reengagement between said accelerating member and said working member and by means of said magnetic coupling; and dissipating said second quantity of kinetic energy by way of an electrical current from said magnetic coupling flowing in a dissipating means.
 15. A method for operating a lightweight impacting working member in a high-speed mechanism comprising the steps of: accelerating said working member forward toward work media while employing resilient means to hold said working member in engagement with an accelerating member; halting the forward motion of said accelerating member while in a displaced position while allowing said working member to continue in essentially free flight toward said work media and while stretching said resilient means; limiting the impact of said working member with said work media by engaging said working member with a kinetic energy absorbing stopping means; retracting said working member from contact with said work media and said stopping means with the aid of said stretched resilient means; returning said working member to engagement with said accelerating member; extracting kinetic energy from said working member upon engagement with said accelerating member; restoring said engaged accelerating member and working member to a quiescent home position while simultaneously removing kinetic energy therefrom; and withdrawing additional kinetic energy from said engaged members upon their return to said home position.
 16. A method for operating a print hammer in a high-speed printing mechanism and quickly bringing said hammer to quiescence after operation comprising the steps of: accelerating said print hammer forward toward printable media to be imprinted while resiliently maintaining said print hammer in engagement with a magnetically coupled accelerating member; halting the forward motion of said accelerating member while in a displaced position from accelerating said print hammer and while said print hammer is continuing under propulsion by its own inertia toward said printable media; limiting the impact of said print hammer with said printable media by concurrently engaging said hammer with kinetic energy absorbing resilient stopping means and said printable media; resiliently retracting said print hammer from contact with said printable media and said stopping means; returning said print hammer to engagement with said magnetically coupled accelerating member; extracting kinetic energy from said print hammer upon its engagement with said magnetically coupled accelerating member; restoring said engaged print hammer member and accelerating member to a quiescent home position while also removing kinetic energy from said members via said magnetic coupling; and withdrawing additional kinetic energy from said engaged members upon their return to said quiescent home position.
 17. Energy-absorbing and excursion-limiting apparatus including a penetration stop member for a high-speed impact printing mechanism that also includes a print hammer member suspended from a frame member and movable along a lengthwise axis between a rest position and an extended position wherein engagement with both a printable medium and said energy-absorbing, excursion-limiting apparatus occurs, said energy-absorbing and excursion-limiting apparatus also including: metallic position adjustment means for supporting and for providing vernier position adjustment of said penetration stop member, said metallic position adjustment means including a threaded metallic member connected with a force-multiplying, resolution-increasing lever of the first class, and resilient organic material energy-absorbing means supported on said penetration stop member and position-located by said metallic position adjustment means for engaging said print hammer member near said extended position, reversing movement direction of said print hammer member, absorbing kinetic energy from said print hammer member and converting said kinetic energy into heat energy, whereby said energy-absorbing and excursion-limiting apparatus provides a rigid and position-adjustable limit of travel for said print hammer member together with energy-dissipating means for said print hammer member.
 18. Energy-absorbing and excursion-limiting aPparatus as in claim 17 wherein said resilient organic material energy-absorbing means includes a thermoplastic material jacket member molded around an end portion of said penetration stop member.
 19. Energy-absorbing and excursion-limiting apparatus as in claim 18 wherein the composition of said thermoplastic material jacket member includes a polyester polyurethane material having 4.0 percent to 4.3 percent isocyanate and cured with a 25 percent to 75 percent combination of dichlorobenzidine and methylene bis(ortho-chloroaniline) at 85 percent stoichiometry.
 20. Energy-absorbing and excursion-limiting apparatus for a high-speed impact printing mechanism that includes a print hammer suspended by cantilever flexure springs from a frame member and movable along a lengthwise axis between a rest position and an extended position wherein engagement between said energy-absorbing and excursion-limiting apparatus and plural portions of said print hammer and flexure springs occurs; said energy-absorbing and excursion-limiting apparatus comprising: plural first resilient energy-absorbing stop member means each larger than said cantilever flexure springs and each in rigid connection with said frame member adjacent each of said cantilever flexure springs for engaging a large portion of each of said cantilever flexure springs in said extended position and for removing kinetic energy from said cantilever flexure springs upon said springs approaching said extended position; and second resilient energy-absorbing stop member means rigidly connected with said frame member adjacent said print hammer for engaging said print hammer in said extended position and for removing kinetic energy from said print hammer upon said print hammer approaching said extended position; whereby separate energy-absorbing means members are provided for kinetic energy removal from said flexure springs and for kinetic energy removal from said print hammer and the severe flexing of said flexure springs by the rapid and bilateral transfer of kinetic energy between said print hammer and central portions of said flexure springs during impact of said print hammer at said extended position is minimized.
 21. Energy-absorbing and excursion-limiting apparatus as in claim 20 wherein said plural first resilient energy-absorbing stop member means includes a plurality of neoprene rubber energy-absorbing pad members, there being one pad member for each of said cantilever flexure springs.
 22. Energy-absorbing and excursion-limiting apparatus as in claim 21 wherein said neoprene rubber is a soft neoprene rubber having a hardness near 10 on the Shore A durometer scale and said pad members are substantially flat in configuration. 